||These can be a
country as a whole, or a region, or a specific population like for e.g.
school children, infants or cardiac patients for whom the application of the
trial results will be beneficial. There may be initial differences in these
populations itself. They may contain urban areas, rural areas, people with
different socio-economic status, living in different places with varying
geographical and seasonal characteristics and having different life-styles.
But these areas or regions may also be inter-related in some aspects.